Extended Endoscopic Endonasal Approach for a Giant Parasellar Epidermoid Cyst

Epidermoid cysts are rare lesions which typically grow slowly. For this reason, these lesions are usually discovered when they are already very large. The parasellar location is no exception to this rule and may involve the cavernous sinus or the Meckel cave. We present a 34-year-old female patient without past medical history who was admitted in our tertiary referral center for episodes of diplopia in the right lateral gaze and right trigeminal dysesthesias. Brain magnetic resonance imaging (MRI) showed a large right parasellar mass with mixed intensity signal on the T1 and T2 sequences, without contrast enhancement and a typical hypersignal intensity on diffusion-weighted sequences evoking an epidermoid cyst. We discuss the radiologic criteria which differentiate the lesions originating in the cavernous sinus from those of the Meckel cave ( Figs. 1 and 2 ). Parasellar tumors may be approached through classical transcranial approaches such the epidural temporopolar or the subtemporal approach which involve a significant degree of brain retraction. The last decade witnessed the advent of extended endonasal approaches which offer an interesting alternative and avoid the manipulation of the brain. We used the endoscopic transpterygoid approach in our patient and we were able to achieve an excellent clinical and radiological result. We discuss the nuances of the technique and present the surgical steps of the procedure ( Figs. 3 and 4 ). The endoscopic endonasal approach represents an excellent therapeutic option for parasellar lesions. A thorough knowledge of the anatomy and experience with endoscopic techniques are obvious prerequisite. The link to the video can be found at: https://youtu.be/QonSvHrCwOU .